The invention relates to a junction diode comprising semiconductor alloys. Some devices, as in Herner et al., U.S. patent application Ser. No. 10/326,470, “An Improved Method for Making High Density Nonvolatile Memory,” filed Dec. 19, 2002, (hereinafter the '470 application), which is hereby incorporated by reference, employ a vertically oriented semiconductor junction diode. Dopant types and levels may be varied throughout the diode, but the entire diode is formed of a single semiconductor or semiconductor alloy.
The present application pursues other methods of preparing a junction diode to improve device performance. In general, silicon-germanium diodes can provide higher forward and reverse currents than comparable silicon diodes as taught in the '470 application. It is preferable to minimize the reverse current and maximize the forward current.